President Obama, not known for brevity, won’t be playing by Twitter’s 140-character rule when he answers questions posed on the social-media website Wednesday in a town-hall format.

Everyday Twitter users must limit their “tweets” to the popular social network’s space requirement. But Mr. Obama will answer questions by speaking on a live webcast, rather than typing short responses on Twitter.

White House communications director Dan Pfeiffer said the event will be a “conversation” with the president, because Twitter followers will be able to respond to Mr. Obama’s answers in real time. It’s set to start at 2 p.m. from the East Room of the White House.

Not restricting the president’s replies is probably a wise move, from the administration’s perspective. The president’s first answer at his news conference on June 29 covered a wordy 4,515 characters — enough for more than 32 separate “tweets.” His opening statement at a Facebook town-hall event in April consisted of 3,834 characters.

White House spokesmen said Twitter officials will screen the questions and control the event, but the administration chose the topic: jobs and the economy. It’s the central theme of Mr. Obama’s early campaign events as he seeks re-election. The gatekeeper for the town-hall meeting is Twitter co-founder Jack Dorsey.

There are more than 2.25 million followers of the White House’s Twitter account. Mr. Pfeiffer said it is “no longer sufficient” for a president to communicate with the public through the mainstream media. Mr. Obama has made much greater use of social networking in his presidency and his campaigns than previous presidents.

“We’ve entered a different information age,” Mr. Pfeiffer said. He noted that people increasingly obtain information on mobile devices, which lend themselves to relatively short pieces of data.

Thousands of questions had been submitted in advance to the hash tag #AskObama by midday Tuesday, many with a partisan edge. A follower named “demsforprogress” asked, “How many jobs have been lost due to Republican budget cuts?” Another question, from “appleacolyte,” asked, “why are you demagoguing GOP reform proposals to prevent a debt crisis? Do you care about enormous deficits and debt at all?”

Then again, “Kenzie2011” posed this question for the commander-in-chief: “What is your favorite type of food? :)”

Mr. Pfeiffer and White House Director of New Media Macon Philips said the town hall is an opportunity for Mr. Obama to connect with Americans around the country. Thirty people who submitted their names on Twitter were chosen by the White House to attend the session in the East Room with the president.

Administration officials said Twitter will collect demographic data of the participants in the event, but only information that has been previously disclosed by Twitter users on their accounts.

“We’re very much looking forward to … seeing what they come up with,” Mr. Phillips said.